And then cometh the day when the
arm of the Lord shall be
revealed in power in convincing
the nations ... of the gospel of their salvation. For it
shall come to pass in that
day, that every man shall hear the fulness of the gospel in his own tongue, and in his own language, through those
who are ordained
unto this power, by the administration of the Comforter, shed forth upon them for the revelation of Jesus Christ.
Doctrine
& Covenants 90:10-11